Being a macro lover and lazy player (when I can get away with it), I have some macros that work great for a lazy disc priest. I've only used them in LFR, but they should work fine in real raids, too.

These macros are simply designed to let you do Atonement healing as long as you have no target selected (i.e. being lazy). If you use an addon like Clique for mouseover healing, it will still function. Obviously, these could also be adapted for mouseover healing by using additional conditions to the macros.

The above macro will cast Prayer of Mending at your target (if an ally) or at your focus if you have no ally targeted. This is a dumbed-down version of the actual macro I use (which is set up to combine PoM and SW:D into a single button for both Disc and Shadow specs).

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All of these macros can be adapted for other spell combinations, of course, and/or given more complicated conditions (as space allows).

I never know how much others know about macros (as I am not the most knowledgeable by any means), so I'll risk sounding arrogant and say: if you need any help or have any questions, feel free to ask.